U.S. Pat. No. 4,947,196 and International Patent Publication No. 90/04254 disclose a photographic camera having a roll film and a magnetic head, the former having a magnetic layer containing magnetic particles that enable reading on the back of the photographic film. According to high improvement technique, information used to distinguish the types or manufacturers of light-sensitive materials, information relating to conditions under which photographs are taken, information. relating to customers, information relating to printing conditions, information relating to reorder printing and other information can be magnetically inputted in and outputted from the magnetic layer on the film, so that it becomes possible to improve printing quality, make printing operation efficient and make photofinisher's office work efficient.
However, when information is inputted in a photographic film from a camera, the above magnetic recording system requires providing a magnetic head in the camera, and also requires a mechanism for holding the magnetic head, bringing about the disadvantage that the camera not only must be made large-sized but also can be expensive.
In the meantime, as measures against such magnetic recording, a method of optically recording information is known, which is a method comprising recording information on a photographic film by the use of a light source, followed by photographic processing to set the information stationary. Japanese Patent Publications Open to Public Inspection [hereinafter referred to as Japanese Patent O.P.I. Publication(s)] No. 96635/1991 and No. 116137/1991 disclose a method of recording-image-trimming information on a film by using an LCD as a light source; Japanese Patent O.P.I. Publication No. 161727, a method of optically recording information regarding the position of photographed images on film in the form of bar codes; Japanese Patent O.P.I. Publication No. 135535/1991, a method of optically recording information concerning photographing conditions on a film in the form of dot codes; and Japanese Patent O.P.I. Publication No. 125543/1992, a method in which information of districts where photographs are taken is optically recorded on a film in the form of numbers or letters.
These are so designed that the information is optically recorded mainly on non-image areas of a film and can be effectively recorded in smaller areas.
As light sources are made small-sized in recent years, compact and inexpensive cameras can be made available even if the light sources are provided in cameras as optical recording units.
Since, however, the proposals hitherto made are still in the stage of application of a fundamental principle of optical recording, no sufficient discussion has been made in order to provide an optimum combination of a writing light source, properties of a light-sensitive material, a reading light source and so forth that are important in the optical recording. Accordingly, nothing has been accomplished more than the recording of dates of photographing in pictures, and no wide practical use as information processing has been made. Moreover, since the optically recorded information, which is recorded as colored dye images in photographic films (light-sensitive silver halide color photographic materials), may undergo variations in color-forming density because of influence by non-uniform degrees of activity and exhaustion of processing solutions in photofinishing laboratories, and hence there is a disadvantage that read errors may occur. Thus, it is sought to immediately solve the above problems.